Johanna Schwartz – “The really challenging part is developing orthogonal photoinitiators. Once this is done, the material space capable of being used in this multi-material process can really start to broaden”

Johanna Schwartz is graduate student in chemistry who has a BA in chemistry and biology. She worked on various research projects, from synthesizing more efficient hydrogen fuel cell polymers, improving the synthesis and purity of cuprous oxide, and even identifying and characterizing thin phytoplankton layers in the Sargasso Sea. For her Bachelor’s thesis research, she worked with Dr. David Myers at Simon’s Rock, focusing on natural product synthesis. Specifically the research focused on the synthesis and biological testing of antibiotically and antifungally active alkynoic acids and butenolides. Johanna officially joined Prof. AJ Boydston’s group in the Department of Chemistry at UW in December 2014. She currently focuses on increasing the material scope and complexity of 3D printing through novel stimuli-responsive polymer synthesis and multi-material process development, primarily for melt material extrusion and DLP 3D Printing.

Johanna, could you let us know about your background and what brought you into 3D printing in the first place?

I grew up in Las Vegas, NV, and have always been interested in science. When I was younger, I wanted to be sure I knew what field I wanted to go into, and I’ve been lucky enough to have had a broad range of scientific experiences. I’ve made hydrogen fuel cell polymers under Prof. Chulsung Bae at UNLV, devised a way to synthesize pure cuprous oxide under Prof. John Ketterson at Northwestern, and sailed on the SSVCorwith Cramer doing oceanographic research studying phytoplankton under Dr. Jeff Schell through SEA Semester. Ultimately, I culminated my undergraduate degree synthesizing and testing the antibiotic and antifungal properties of butenolides and their target precursors under Prof. David Myers at my undergraduate institution, Bard College at Simon’s Rock. Through all of this research, I was able to decide what I really wanted to work on, and this ultimately led me to chemistry and to polymer synthesis. When I started working under Prof. AJ Boydston at UW, I was set on synthesizing complex stimuli responsive polymers. I never would have imagined incorporating 3D printing, but my work in this group and my interactions and collaborations with other departments led me to shift focus to what I do now. Currently, I focus on using chemistry to tackle some of the current problems with additive manufacturing, as well as develop new materials that will enable us downstream to incorporate these stimuli-responsive polymers into 3D printed objects.

What was your very first experience with 3D Printing?

In my senior year of college, I was part of a 3D printing club that built a filament printer from a kit. While I was not the most active member, I still have my first pair of 3D printed earrings.

I understand you are currently working on new material development for 3D Printing applications. Could you tell us a bit more about the scope of your research?

There are two primary objectives of my research. One is expanding the scope and complexity of polymers being 3D printed. My second objective is to develop new methods of 3D printing that will help facilitate the use of these new materials.

What 3D Printing applications would be concerned?

I primarily work with DLP 3DP vat photopolymerization, and my ultimate goal is to develop multi-material printing with a mixed vat of resin. This would enable the ability to spatially control the mechanical properties of the 3D printed objects, as well as their potential stimuli response.

How challenging is it to develop new 3D Printing materials?

Photopolymerization chemistry has been around forever, but while the scope of materials that are capable of being photopolymerized is huge, the scope of materials currently used towards 3D printing is much smaller. I am constantly reminded of how non-trivial it is to adapt a process and material towards 3D printing. It really takes the right blend of monomer, photoinitiator, photosensitizer, dye, pigment, and other additives to make a print work. Once the print is working effectively, there is a whole other round of optimization to get the mechanical properties and complex responses desired. The optimization process itself is not that challenging, just time intensive. What I think was the most challenging part for me was amassing the knowledge necessary to know what to optimize. My lab jokes that I am not a chemist anymore, but a materials scientist or a mechanical engineer. While my chemical background really laid the foundation for me, I’ve had to build up a lot, reading into other fields, to get to where I am now (and I’ve still got a long way to go!).

When talking about multi-material process development: what materials can be combined easily? What materials can’t, and why?

In terms of vat photopolymerization additive manufacturing, I think if this was easy it would already be done. The key here is to have two orthogonal polymerizations and two orthogonal photoinitiators. An orthogonal polymerization system that I think everyone can recognize is the epoxy/acrylate based polymerizations. Carbon has utilized this to make some of their resins, initially photo-curing the acrylate monomers, entrapping epoxy monomer within the printed object which they can then thermally cure. The really challenging part is developing orthogonal photoinitiators, such that you control which polymerization occurs dependent on wavelength. Once this is done, the material space capable of being used in this multi-material process can really start to broaden. We’ve made some great headway with the research, and are fortunate to have support toward commercialization through the Amazon Catalyst program at the University of Washington.

What exactly is your area of expertise in this research work?

I think the simplest answer to this is that my area of expertise is problem-solving. My research ranges from materials development and synthesis to 3D printing, mechanical testing, and computational analysis, and as such I’ve had to learn a lot. I came into this with a chemical perspective, but this research is really multi-disciplinary. Whenever something is not working, I completely focus on that problem until it is solved, so that I can move my science forward. This includes relying heavily on collaborations with other departments and being willing to ask for help when I am out of my element. I’ve been really grateful for this help, and I think it has made me a better scientist overall and allowed me to solve the problems I’ve faced and progress in my research.

Do you have a favorite 3D Printing tool?

I’m particularly fond of our SeeMeCNC Droplit, as it was the first printer I built in this lab, and started my research into 3D printing. As far as materials go, I also work a little with melt material extrusion, and my favorite material is the mechanochromic filament that we have developed. It incorporates a spiropyran mechanophore into polycaprolactone thermoplastic, and when we stretch the material it turns this awesome purple color. It also turns purple in UV, which is really fun on those rare sunny days in Seattle.

Have you run into any challenges from being a woman researcher?

I really haven’t, and I’ve been really grateful for that. The environment at UW socially is pretty amazing, and through my collaborations among many STEM departments, I have almost always worked with at least one other female graduate student or researcher, which is not something I think I could say elsewhere. AJ has also been an amazing PI. He is always challenging me but is also incredibly supportive, and I feel I’ve really grown because of him.

Anything exciting coming up you’d like us to know about?

I will be giving a talk at a symposium at UW, titled Additive Manufacturing and Functional Materials June 22-23. This is the second year we have had an additive manufacturing conference, and I’m hoping we can make this an annual thing. I’ve had the privilege of helping co-organize this year’s symposium with AJ, and I’m really excited to see how it turns out. With the help of AJ’s co-chair, Henrique de Amorim Almeida from the Polytechnic Institute of Leiria, we’ll have a much larger international crowd this year, both in terms of attendees and speakers. This will be the largest audience I’ve spoken in front of, but I am incredibly excited for this opportunity to share my research.

What is the most impressive or impactful use of 3D printing you’ve seen so far?

I feel like as a chemist in this field, I have two answers to this question. When it comes to some of the most impressive engineering or mechanically-based uses of 3D printing, I’m always amazed at the work that goes into prostheses and developing designable and workable devices to help people go through their daily lives. I think organizations like e-NABLE are doing some pretty amazing and positive things in the world right now, and I’d love for these kinds of 3D printing organizations to become more of a common thing, tackling problems that directly face us right now with the technology already available to us. At the same time, I am also always impressed with the fundamental research that occurs in 3D printing that is advancing the capabilities of printing, and the materials that it is possible to print. I think I’m a little biased in that I always find papers that are at the interface of multiple disciplines, particularly those that incorporate stimuli-responsive or complex materials, the most impressive. Work like that of Jennifer Lewis, George Whitesides, and Nicholas Fang comes to mind.

What makes the 3D printing industry particularly interesting for you?

I really like the ease of design modification in 3D printing. The ability to be able to change simple design parameters and input files, and completely adjust the outputted object both geometrically and mechanically, is really exciting. I would really love to make 3D printing a much more capable manufacturing process, with a much wider scope of materials usable with a much wider range of potential downstream applications. I think it takes chemists in this field to really make that happen.

What do you think of the 3D printing industry today? And how would you like to see it evolve?

I think the potential for the 3D printing industry is huge. There is a reason so many people and companies are excited by it, and investing in it. I still think that there is a lot of open space for improvement in the current industry to meet those expectations, and I think it is going to take some fundamental research to make the evolution happen. In a perfect world, I would love to see downstream objects made by 3D printing that have the exact same mechanical properties as objects made in other manufacturing processes like injection molding, but with the added benefit of direct modifiability. No layering defects, no limits in what materials are capable of being printed, and no geometric or scalable limits. That would be really amazing, but it is going to take a lot of research to get there.

In your opinion, how could we encourage more women to become involved with 3D Printing?

I feel like my experiences with technology growing up really helped me get into this field. The major contributing factor that enabled me to get into the 3D printing field was that when we got that first Droplit kit, I felt like I could build and use that printer without much problem. If I had not built that printer, our group probably would not have gotten into vat photopolymerization 3D printing (or at least I would not have). My mom is a computer consultant, and she taught me how to build and take apart computers, and some basics of coding. This experience, coupled with many other experiences I’ve had in my life, like robotics team in high school, where I had to work with tools, machinery, design modification, and programming are what made my interest in this field possible today. In that sense, I think programs and clubs like robotics in schools are super important. By starting early, and developing something like “take apart days” that I had in science class in middle school where everyone could freely take apart old broken machines and computers, would be really useful. This would rely heavily on program development with schools and the support of teachers, but I think it could really help bridge the gender gap in hands-on fields in the future.

In terms of the present, one of the primary ways I think we can get more women into this field is to get them aware and comfortable with the current technology in an open and accessible way. Filament 3D printers can mostly print themselves, and if we could provide workshops that would give women the opportunity to take apart, build, modify, and use 3D printers kits towards a project, I think they would take this knowledge with them and keep going. The University of Washington has free community-based facilities for students called CoMotion Makerspaces that let them use 3D printers and other prototyping tools towards their own individual projects for free. I think spaces like these are really beneficial towards getting more people involved in 3D printing. I would love to see the development of events focused on 3D printing in these spaces, especially events targeted towards women.

Thank you for reading and for sharing!

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